Rotary cutter



P 1929- F. P. MILLER 1,729,047

OTARY CUTTER Filed July so. 1926 2 Sheets-Sheet 1 Sept. 24, 1929. F. P. MILLER 1,729,047

ROTARY CUTTER Filed July 50 1926 2 Sheets-Sheet 2 Patented Sept. 24, 1929 UNITED, STATES PATENT. OFFICE FRANK r. MILLER, or MEADVILLE, PENNSYLVANIA ROTARY Curran Application filed July 30,

This invention relates to rotary cutters such as milling cutters, counter bores and reamers, boring bars and has for an lmportant object the provision of simple means whereby 5 the blades thereof may be positively anchored in place to withstand the strain to which the same are subjected in use.

More specifically an important object is to provide an inserted blade rotary cutter 10 in which the walls of the slots converge slightly toward the bottom of the slots and in which the blades are slightly wedge shaped parent during the c scription.

In the accompan ourse of the following dein drawin s formin a h 13 part of this application and in which like numerals are em loyed to designate like parts throughout t e same, I

Figure 1 is a fragmentaryperspective of a rotary cutter embodying the invention.

Figure 2 is a fragmentary end elevation of the improved r in section.

Figure 3 is 2. gr

otary cutter, parts being oup perspective illustrating one of the blades and the holding and ad justing means therefor.

Figure 4 is a fragmentary plan view illustrating a slight modification of the invention.

Figure 5 is a gr ing the blade and for shown in Figure 4.

Figure 6 is a fragmentary oup perspective illustratthe holding'means thereplan 7 View illustrating another mechanical expression of the invention.

Figure 7 is a gr ing the blade and oup perspective illustratthe holding and supporting means therefor shown in Figure 6.

. Figure 8 is a fragmentary plan view illustrating a further modification of the invention.

Figure 9 is a gr oup perspective illustrat- 1926. Serial No. 125,956.

ing the blade and the holding and fastening means therefor shown in Figure 8.

Figure 10 is a fragmentary plan view illustrating another form of invention.

Figure 11 is a group perspective illustrat ing the blade and the supporting and fastoning means therefor shown in Figure 10.

- Figure 12 is a detail sectional view illustrating a still further modification of the invention.

Figure 13 is a group perspective illustrating the blade and the holding means there for shown in Figure 12. Figure 14 is a detail sectional view taken on line 14-14 of Figure 12.

In the drawing the numeral 5 designates the body of a milling cutter, a reamer or the like which body is provided with an annular series of slots 6 for the reception of blades 7 Attention is especially invited to Figure 2 which illustrates that the side walls of the slots 6 converge at angles of approximately five degrees and that the side walls of the blades correspondingly converge so that the blades may be firmly'wedged in place in such a manner that the blades are amply able to withstand the strain to which the same are subjected. Figure 2 illustrates that the inner edges of the blades are at all times spaced from the bottom walls of the slots so that blades may be firmly wedged in place by a means to be described.

In carrying out the invention the sides of the blades may be longitudinally grooved as indicated at 9 to partially receive locking pins 10, thelocking pins being forced inwardly and laterally by "one or more set screws 11. "The inner endsof the set screws are provided with conical ends which, when forcibly engaged with the locking pins 10, 90 will movethe same inwardly and laterally into binding engagement withf the blades, whereby to move the blades inwardly in substantially radial directions to wedge the blades in place. When the-blades are thus 95 forced inwardly the same will have binding engagement with the side walls of the slots and will be positively held against radial and endwise shifting.

Reference to Figure 3 will show that each 100 blade 7 is grooved or serrated transversely as shown at 12 for engagement by the laterally projecting rib at one side of a locking key 14. The body of the locking key 14 extends through the enlarged portion of a keyhole groove 16 in one side wall of the slot 6 while the rib at one side of the key extends entirely through the restricted portion of the slot 16 and is received in one of the transverse grooves 12, whereby the end thrust on the blade is effectively transmitted to the'body. It will be seen that the rib at one side of the key 14 is engaged by the side walls of the restricted portion of the keyhole groove 16 whereby the key is held against turning under the influence of end thrust on the blade.

In the form of invention illustrated in Figures 4 and 5 the side walls of the slots may converge slightly toward the bottom walls of the'slots and the side walls of the blades 14 may correspondingly converge so that the blades may be snugly fitted in the slots. In carrying out thisform of invention one side of each blade 14 may be grooved longitudinally as indicated at 17 for there ceptionof a locking pin 18, the locking pin, of course, being forced into binding engagement with the blade by one or more set screws 20 or other suitable fastening devices. In this form the key 24 is not employed.

Attention is now invited to Figures 6 and 7; which illustratethat the sides of the blades 30 may converge slightly to correspond to the similar inclination of the side walls of the slots 31, so that the blades may be firmly In this form of invenwedged into place. tion one side of the blade maybe grooved 1ongitudinally asindicated at 32 for the receptionxof a locking pin 34, the lockingpin being adaptedto bedriven inwardly and laterally andinto binding engagement withthe blade 30' by set screws 36 or: other suitable fastening devices.

The end thrust on each blade'30 is transmittedto the body of the cutter by a cylindricalkey 37, the blade being grooved transversely as indicated at 38 topartially receive the key. One side wall of the slot 31 may be grooved as shown at 40 for the reception ofthe key 37 and it is believed to be obvious, es pecially by reference to Figure'6, that the key 37 will effectively transmit-thethrust on theblade 30'to the od y'and that the multiplicity of grooves 38will providefor ad- I justment of the cutter.

Inthe form of invention illustratedin Fig- P88 8. and 9: the sides of the blade 44 may converge slightly toward the inner edge thereofto correspondto the similar inclinas tionof the side walls of the slot 46, whereby the blade may. be firmly seated. Of course the blade 44 at no timeengages the bottom wall of the slot 46.

One side of the blade 44 is groovedlongitudinally asshownat 48,.to partially receive a locking pin 49 adapted to be driven laterally and inwardly into binding engagement with the blade h set screws 50 or other suitable fastening evices. The end thrust on the blade 44 is effectively transmitted to the body through the medium of a wedge shaped key 52, a portion of which is selectively received in one of the transverse grooves 53in one side of the blade, while the remaining portion of the key 52 is received in a dove-tail groove 55 in one sidewall of the slot 46. The key 52 provides an especially effective thrust transmitting means by which the blades are firmly heldinplace during use. The grooves 53 conform in cross-sectional formation to the crosssectionalformation of that portion of the wedge shaped key 52which they receive to avoid looseness between the parts.

In the form of invention illustrated in Figures 10 and 11 the sidewalls of the blademay converge slightly toward the inner edges thereof to correspond to the inclination of the side walls-of the slot61 and the blade may have one side provided witha longitudinal groove 62 which gradually deepens toward the rear end thereof for the reception of a locking key 64. The locking pin 64.

gradually increases in lateral dimension; to,

ward one end thereof tofill the gradually deepening groove 62 and-to positively avoid endwise movement of the blade 60 under the influence of the strain to which the same is subjected.

The locking pin 64 may in turn be heldinplace by'set screws 66 or other suitable fastening devices, the forward portions of which are tapered and are selectively engaged with blade, whereby the bladeis firmly anchored in place.

In the form of invention shown'in'Figures 12 to 14 inclusive, the sides of the blade-7O mayconverge toward the inner edge thereof to correspond to-the'inclination' of the side walls of the slot 71, wherebya wedging" fit isprovided for the'blade,

Figure 13 illustratesthat one side offthe blade 70 is grooved as indicated at 72. to. partially leceivea locking; pin 73, the rear portion: of which is provided with aright angle bend to define a shoulder or abutment 74, adapted to be flatly engaged" withf the rear end of the blade 70 to=hold the blade against endwise shifting. F igure: 12-:ad.-,- mirably illustrates this point. I

The locking pin '73 is, in. turn, .forcedi-into binding engagement with the: blade 70 by fastening devices 75 in the nature 'of set screws or the like. F igure14" clearly shows that the forward portions of the fastening devices are conical and will force the lock- CJI ing pin 73 into firm binding engagement with the adjacent portion of the blade 70, to positively hold the blade in place against radial and endwise shifting. When the pin 73 is thus locked in place, the abutment 74 will positively back the blade and hold the same against endwise movement in one direction.

Having thus described the invention, what is claimed is:

l. A rotary cutter comprising a body having slots provided with converging side walls, blades in said slots and having converging side walls adapted to flatly engage the converging side walls of said slots, a side wall of each slot and a side wall of each blade being provided with an opposed longitudinal groove, locking means in the grooves, and set screws engaging said locking means to force said blade inwardly into binding engagement with said converging side walls, the inner edges of said blades being free and constantly spaced from the bottom walls of said slots.

2. A rotary cutter comprising a body having slots, blades in said slots, one of the side walls of said slots being provided with key hole grooves having restricted portions, and locking keys in said grooves and having lateral ribs extending through the restricted portions of the keyhole grooves and having locking engagement with said blades, the sides of said restricted portions having engagement with said ribs to hold the ribs against turning.

3. A rotary cutter comprising a body having slots, one of the side walls of which are provided with grooves having restricted portions, blades in said slots and being provided with grooves, and locking keys snugly received in the grooves in the side walls of said slots and having lateral ribs snugly extending through the restricted portions of said grooves and into the grooves in the side walls of said blades.

4. A rotary cutter comprising a body having slots, one of the side walls of which are provided with grooves having restricted portions, blades in said slots and being provided with grooves, and locking keys in the grooves in the side walls of said slots and having lateral ribs snugly extending through the restricted portions of said grooves and into the grooves in the side walls of said blades, and separate locking means for said blades.

5. A rotary cutter comprising a body having a slot, one side wall of which is provided with a substantially radial dove-tail groove,

a blade in said slot and having a dove-tail groove, and a wedge-shaped locking key snugly received in the first and second named grooves and transmitting end thrust on the blade to the body.

6. A rotary cutter comprising a body having a slot, one side wall of which is provided with a substantially radial dove-tail groove, a blade in said slot and having a dove-tail groove, a wedge-shaped locking key received in said grooves and transmitting end thrust on the blade to the body, and additional locking means for holding said blade in place.

7. A rotary cutter comprising a body having a slot, one side wall of which is provided with a dove-tail groove opening out through the periphery of the body, a blade in said slot and having a dove-tail groove, a Wedgeshaped locking key received in said grooves and transmitting end thrust on the blade to the body, and additional locking means holding said blade in place, the sides of said blade and the sides of said slots converging toward the bottom of the slot.

8. A rotary cutter comprising a body having a slot, a blade in said slot and having a longitudinal groove gradually deepening toward the rear end thereof, and a locking pin partially received in said longitudinal groove and gradually increasing in lateral dimension only toward the rear end thereof, the radial dimension of the pin being substantially unchanged throughout.

9. A rotary cutter comprising a body having a slot, a blade in said slot and having a longitudinal groove gradually deepening toward the rear end thereof, and a locking pin partially received in said longitudinal groove and gradually increasing in lateral dimension only toward the rear end thereof the radial dimension of the pin being substantially unchanged throughout, and fastening means for said pin, the sides of said blade and the sides of said slot being correspondingly inclined.

In testimony whereof I afiix my signature.

FRANK P. MILLER. 

